The measurement of the Epstein-Barr viral load in peripheral blood has been recognised as an important way of monitoring the response to treatment in patients with Epstein-Barr virus (EBV)-related malignancies. In particular, EBV load in transplant recipients can be used as a predictive parameter for Post-transplant Lymphoproliferative Disorder (PTLD). The aim was to develop a rapid and reliable PCR protocol for the quantification of the cell-associated EBV genome. Real-time PCR using TaqMan methodology was established. This technique was applied to determine the EBV load in various study groups including healthy controls, transplant recipients, patients on haemodialysis, and patients with infectious mononucleosis. The baseline level of EBV genomes in the immunosuppressed renal transplant recipients was significantly different from that in the healthy controls.